text:
What special training is required to fly in the Washington DC area?
I remember hearing that special training was required to fly into the Washington DC area and that it didn't really apply to me (maybe it was VFR only?).  What is the requirement and what must you do when flying in the area?

Besides just the SFRA, there are several special use airspaces within the DC metro. The training provides an overview of this, so I recommend taking it whether you are technically "required" or not. It's online, relatively painless, and just good sense.

There is a training course on FAASafety.gov that all pilots operating VFR flight within 60nmi of Washington DC must take.
Since I assume you are flying IFR, you would not be required to take it.
From AOPA:

All of the following operations are exempt from the training
  requirement:

Pilots operating under instrument flight rules (IFR);
Law enforcement, military, and aeromedical operations; and
A pilot who must deviate to the extent necessary to address an emergency situation.

You are correct.

Starting on February 9, 2009, any pilots flying VFR within a 60 nautical miles (110 km) radius centered on the ADIZ are required to complete training about the ADIZ. This training can be completed online through a course called "Navigating the New DC ADIZ". Pilots may also complete the required training by attending a seminar offered at a Flight Standards District Office. Pilots must obtain a certificate which proves that the training has been completed. This certificate is not required to be carried with the pilot, but must be produced when requested from law enforcement or other agencies. Pilots flying IFR are not subject to this requirement. [src]

This is not a TFR, but a permanent special flight rules area. More info can be found here on flying around DC in general.
The specific rules can be found in FAR 91.161:

(a) Operations within a 60-nautical mile radius of the Washington, DC VOR/DME under visual flight rules (VFR). Except as provided under paragraph (e) of this section, no person may serve as a pilot in command or as second in command of an aircraft while flying within a 60-nautical mile radius of the DCA VOR/DME, under VFR, unless that pilot has completed Special Awareness Training and holds a certificate of training completion.
(b) Special Awareness Training. The Special Awareness Training consists of information to educate pilots about the procedures for flying in the Washington, DC area and, more generally, in other types of special use airspace. This free training is available on the FAA's Web site. Upon completion of the training, each person will need to print out a copy of the certificate of training completion.

Is that Training still available? I was not able to locate it, only a Checklist dated 11/15/07.


text:
What is the difference between OAT, RAT, TAT, and SAT?
When I first started flying jet aircraft, I found different instruments that measure temperature in different ways and it was quite confusing.
What is the difference between Outside Air Temperature, Ram Air Temperature (RAT), Total Air Temperature (TAT), Static Air Temperature (SAT), and any that I might have missed?

As you measure temperature moving at high velocities, your outside thermometer will measure a higher temp than what is actually outside (what a non-moving thermometer would get). That's because as the air rams into your thermometer it gets a little bit compressed, and that makes it heat up a little bit.
Amazingly, some smart people have even calculated how much that "ram rise" is, and you can actually compensate (well, in theory) from the indicated temperature to calculate what the actual outside air temp is:
$$Ram~Rise=SAT\times0.2\times{M}^2$$
Where $SAT$ is Static Air Temperature in Kelvin, $M$ is Mach number
Problem is, not all instruments will compress that air in the same way, and not all of them will pick up this Ram Rise entirely. So they will publish a $K$, a ram-rise-coefficient (also called recovery factor) meaning how much of from the theoretical Ram Rise they actually pick up.
(OAT/SAT) Static Air Temperature = noted as $T_S$, actual temperature of the air outside, the same your thermometer will pick up if you were not moving
(say, in a balloon?)
(RAT) Ram Air Temperature = noted as $T_M$, actual measured temperature by your instrument.
$$RAT=SAT+k\times{Ram~Rise}$$
(TAT) Total Air Temperature = noted as $T_T$, total temperature as measured by an instrument with $K$-coefficient of $1$.
$$TAT=SAT+Ram~Rise$$

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text:
How can I legally land VFR in class D airspace with low and few clouds?
This question is a bit specific because it applies to an actual situation I'm observing for a flight I'm looking to make tomorrow.
I'm a Non-IFR rated pilot looking to fly class D airspace. My destination airport is anticipated to have clouds (FEW @ 1,000 ft). In this case, it seems like it would be pretty easy for 1 single cloud's position to make it impossible for me to land at the airport despite being able to (likely) safely land. For example, if the cloud were over the middle of the runway, but I had plenty of runway at my landing end, it's technically possible that the requirements for distance from clouds could keep me from landing here.

I realize the example is trite, but hopefully this illustrates my point.

What is the appropriate way to handle this situation as a pilot?
I'm calling up tower before I have a visual on the airport (which would be the case in this situation) would they likely deny clearance to land due to knowing that a singular cloud sits out there and would cause a bust the visual flight rules or might they clear me without regard to the rules?
What is considered cloud clearance in this situation? I realize clearance is easy to determine if you are directly above, below or adjacent to a cloud, but more commonly you'll be at some sort of angle to the cloud as in the picture. Shown are two ways to consider cloud clearance (in red and blue lines)

As for #2, no. It's up to you to stay the required distance from clouds. There's no way we can see from the tower how far you are from a certain cloud, and even if we could we really have better things to do.

ATC is not the cloud police.

Related - https://aviation.stackexchange.com/q/345/34686 , https://aviation.stackexchange.com/a/361/34686

What is the appropriate way to handle this situation as a pilot?

First, tell tower about the problem.  They may be able to assign you a different runway, have you loiter (circle) for a minute or three, etc.  It's likely not the first time this has ever happened.
If necessary ask the tower for a Special VFR clearance.  That changes your cloud clearance requirements dramatically in your favor.  Note that the tower is not allowed to offer this clearance to you - you have to explicitly ask for it.

I'm calling up tower before I have a visual on the airport (which would be the case in this situation) would they likely deny clearance to land due to knowing that a singular cloud sits out there and would cause a bust the visual flight rules or might they clear me without regard to the rules?

J. Hougaard answered this part in the comments - the tower is likely not checking how far you are from a single cloud.

Good point on the SVFR, that makes this situation much more reasonable.

Could the tower really grant SVFR here?  See this ASE answer https://aviation.stackexchange.com/a/361/34686 which states that the airport must be reporting "below VFR minimums".  "VFR minimums" are usually conceptualized as being ceilings lower than 1000' AGL -- see http://learntoflyblog.com/2016/10/17/regulations-vfr-minimums/ .

I agree that SVFR is easiest way to deal with this situation. However, sometimes controllers resist going through trouble of SVFR when its just one or two puffy clouds in the pattern and the reported weather is VFR.

They don't care about one cloud. Its not their responsibility for you keeping your cloud clearances. Especially when weather is reported as VFR. You need to maneuver around or under the cloud for landing. Another regulation is the minimum safe altitude regulation, but it has an exception for landings and takeoff. So if you need to deviate from traffic pattern altitude to maintain cloud clearances by going under or around the cloud, tell the tower what you are doing.

(Scenario: There is a cloud at 1200 on downwind leg. Traffic pattern
altitude is 1000. You see the cloud, and you estimate you need to be at 700
feet to maintain cloud distance. You tell the tower what you are
doing and do it, then proceed with landing. Alternatively, if you're
cleared to land, just start your decent a little earlier on downwind
to 700, maintain that altitude until you're ready to finish the approach.)

This is a good question. Cloud distances are given in horizontal and vertical (above or below) distances, not in diagonal. The square box in your diagram calculates the distances as described in the minimum safe altitudes section 91.119 over populated areas where it states "1000 feet above the highest obstacle within a horizontal radius of 2000 feet." However, the distance in the Basic VFR weather minimums section 91.155 do not use that same description. No where in 91.155 does it talk about keeping 500 feet below a horizontal distance from a 2000 ft radius of a cloud, or any similar language. Therefore, I think the dotted rectangle in your diagram is overly (conservative) and not supported by the language of the section 91.155.

NOTE: the other dotted line in your diagram (blue) is also incorrect because it doesn't capture the 500 ft directly below the edges of the cloud.

Could the tower really grant SVFR here?  See this ASE answer https://aviation.stackexchange.com/a/361/34686 which states that the airport must be reporting "below VFR minimums".  "VFR minimums" are usually conceptualized as being ceilings lower than 1000' AGL -- see http://learntoflyblog.com/2016/10/17/regulations-vfr-minimums/ .

@quietflyer it doesn't say it "must be reporting" below VFR minimums, it says that SVFR is authorized when below VFR minimums. Similarly, IFR can be granted below VFR minimums, but is often filed and granted on clear days. SVFR is a pain for controllers from what I am told, so they sometimes resist or deny the request, but the AIM says under 7-5-1(b) that it can be granted when airport reports VFR, but pilot reports that he cannot maintain VFR. I think you could make the argument that this could include VFR cloud clearances. Although, I would personally just fly under or round the cloud

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text:
What is the safe separation for landing a Cessna-172 behind a commercial airline jet?
When is it safe to land a Cessna-172 after a commercial airline jet has landed?

Personal experience after a KC-135 is about 3 to 5 miles.

It depends on the size of the preceding aircraft. ICAO PANS-ATM-Doc 4444 Air Traffic Management has some values.

5.8.2 · Arriving aircraft
5.8.2.1 Except as provided for in 5.8.l.l a) and b), the following separation minima shall be applied.
5.8.2.l.l The following minima shall be applied to aircraft landing behind a HEAVY or a MEDIUM aircraft:
a) MEDIUM aircraft behind HEAVY aircraft- 2 minutes;
b) LIGHT aircraft behind a HEAVY or MEDIUM aircraft- 3 minutes.

Note that in case of A380, it is more- 4 minutes.
In case of distances, the light aircraft are to be landed 5nm after a medium aircraft, 6nm after a heavy and 8nm after A380.
Note: The categorisation of aircraft is done as below:

4.9.1 Wake turbulence categories of aircraft
4.9.1.1 Wake turbulence separation minima shall be based on a grouping of aircraft types into three categories according to the maximum certificated take-off mass as follows:
a) HEAVY (H)- all aircraft types of 136 000 kg or more;
b) MEDIUM (M)- aircraft types less than 136 000 kg but more than 7 000 kg; and
c) LIGHT (L)- aircraft types of 7 000 kg or less.

Even after waiting the required 3 - 5 minutes, you should still follow the standard advice of Staying above the glide-path of the previous plane, and touching down beyond where they touched down.  When landing: "Stay Above; Land Beyond"

What if it's windy out?

The ATC rules in FAA-land say that if a "small" aircraft (maximum takeoff weight up to 12,500 lbs) is operating under instrument flight rules behind a "super" aircraft (A380 or An225) and less than 1000 feet below it, the minimum radar separation is eight miles between the super ahead and the small behind. This is always the case, including when both are on an instrument approach (and therefore the small cannot maneuver visually to avoid wake turbulence). 7110.65 5–5–4 g1(a)(3).
When radar separation is not being used, i.e. when the small is VFR and not being vectored for an approach, there is no minimum separation outside of Class B airspace, where the standard 1.5 NM separation applies. (Not that it's likely an A380 would be landing at a non-Class B airport, but the An225 might!) But the ATC should without a doubt issue a wake turbulence advisory in accordance with 2–1–20 and 3–10–3 b, and should expect the small to maneuver very far behind the super.
As for the actual landing, there are a few different situations, described in 3–10 and 3–9:

Small is landing behind landing or departing super, same runway. No increased separation beyond standard same-runway separation (lead aircraft must be clear of runway if landing, or 6000 feet down the runway and airborne if departing).
Small is landing behind landing super, crossing runway. No increased separation beyond standard crossing-runway separation (lead aircraft must be through the intersection).
Small is landing behind departing super, crossing runway, super will rotate before the intersection. 3 minutes separation.
Small is departing behind departing super, same runway. 3 minutes or 8 miles on radar.
Small is departing at an intersection (or touch-and-go) behind departing super, same runway. 4 minutes after super rotates.
Small is departing behind landing or departing super, crossing runway, super is airborne at the intersection. 3 minutes.

There are a few more cases involving converging runways, or where two arrivals will cross paths prior to the runway thresholds, that are similar to the crossing-runways cases.


text:
Are runway safety areas for both emergency landings and aborted take-offs?
Is a runway safety area at the end of a runway provided specifically for safe emergency landing of aircraft using it and are required to abort takeoff just before or after reaching the critical V1 speed? Does it mean that at big international airports with a number of runways, each and every runway is to be provided with its own runway safety area?

Yes, the runway safety area is to provide a buffer zone for aircraft that leave the runway for whatever reason, including rejecting a take-off late or by overshooting on landing. It's not specifically for an "emergency landing": sometimes the emergency might only arise during the course of the landing, for example tyres bursting or pilot error.
If it were only for emergency landings, then parallel runways probably wouldn't need to all have a RSA, because the distress aircraft could be offered the one runway that has one. But in fact every runway needs an RSA, because any landing might suffer a runway excursion.

There's also the point that an aircraft could develop an emergency while on final approach, in which case it wouldn't be ideal to abort the approach and set up a new one on the runway with the RSA

@JonStory, the approach was commenced to a long enough runway and that calculation was done for using brakes only, so the runway does not become too short when emergency develops. The runway end safety areas have nothing to do with existing emergencies.

@JanHudec Nothing I said suggested otherwise? I'm just pointing out that when you develop an emergency while on final, you'd appreciate the runway having an RSA - it would be unfortunate to be on short final to a runway without an RSA and have to decide between going around to set up on another runway, or land on a runway without an RSA. Nothing to do with existing emergencies

@JanHudec: "and that calculation was done for using brakes only" - Brakes and spoilers (and airbrakes, too, if so equipped).


text:
How should night time be determined and logged in a fast westbound plane?
You take off from KFLL (Ft Lauderdale, FL) an hour before sunset in a B737. You're heading to KSEA (Seattle, WA).
4:35PM EST plus 6 hours 34 minutes is 11:09PM EST, or 8:09PM PST.  Seattle sunset was 4:22PM PST.
Since the flight went west quickly it delayed sunset. Since it went north in the winter it hastened sunset.
So how does the flight crew split their day and night flying portions?

Record UTC when the PIC declares it to be night, split accordingly
A computer just tells them the answer
The flight crew already have ATP ratings, they don't care for detailed logging anymore
Something else

All of my flying has been roughly north/south at C172 speeds, so it hasn't really mattered more than the rounding error of recording in 0.1hr increments.

In practical terms, your third bullet ("The flight crew already have ATP ratings, they don't care for detailed logging anymore") is probably about right. I logged night & IMC faithfully until going to work for an airline, and I don't think I (or the automated systems that track hours & currencies) have logged a minute of either since then.  At this level, nobody much worries about it any longer.

I don't think many airline crew actually bother to log the day/night breakdown.
At my airline we have different pay rates for day and night flying, so we do care, but the company "Electronic Logbook" tracks the day/night breakdown for us. The system is not 100% accurate and we sometimes get paid more or less day or night then we actually fly in, but it tends to average out over the year.
In the summer, polar routes can be as much as 15 hour flights of daylight, while the same route in the winter can be 15 hours of night flying.
On some flights we will see the sun set, and then rise, and set again, as we chase the sun and our route changes from northwest bound to southwest bound.

Here are some samples of summer/winter, day/night Toronto to Hong Kong flying in my eLog:

Let me point out that for the purposes of logging flight time, night is defined under 14 CFR 1.1 as follows:

Night means the time between the end of evening civil twilight and the beginning of morning civil twilight, as published in the Air Almanac, converted to local time.

This means that sunset is not the deciding factor, but rather the published start and end times of civil twilight.
For the flight details you give, the transition to legal night would probably occur almost two hours into the flight somewhere near Little Rock, Arkansas, around 23:30 UTC at the end of local civil twilight. The specifics of that transition time and location will depend on  ground speed, cruise routing, time spent in the departure routing and climb, and so on.

This same—or a similar—issue arises for slow aircraft over even relatively short distances. Any pilot flying any aircraft during the transition into or out of civil twilight where the time of civil twilight varies between the departure and destination points will face difficulty in determining exactly where and when the transition into legally loggable night time occurred.
When I was logging my first 100 hours of night time, I paid close attention to civil twilight on my flights so as to ensure I was not missing any loggable night time (and to ensure I wasn't incorrectly logging night time). Most of my 100 hours of night flight time took place in a C172 flying cross country into sunset or sunrise. To calculate the actual point where civil twilight began or ended, I consulted civil twilight tables based on my route of flight and interpolated the times to find the proximate location and time that night began or ended.
Now I care less about the amount of night time I have, and generally just log a leg as night if that leg took place entirely during night conditions. I suspect many professional pilots do the same.

14 CFR 61.51 requires a pilot to log:

(1) Training and aeronautical experience used to meet the requirements
  for a certificate, rating, or flight review of this part.
(2) The aeronautical experience required for meeting the recent flight
  experience requirements of this part.

The pilot must include the following information in that log:

(3) Conditions of flight—
(i) Day or night.

Logging night time is required if to be used toward a certificate such as the 100 hrs required the ATP. However, once beyond that requirement, logging night time is only required when documenting recency of flight experience such as night landings.

Did you work out Little Rock by guess and check, or was there a more sophisticated way of getting the answer?

@bartonjs I calculated an approximate time by interpolation, considering departure time and cruise speed. I then checked the location to verify the end of civil twilight occurred at the right time.


text:
Why is there such a difference between the study material for the FAA and EASA ATP knowledge tests?
What's the difference between the FAA & EASA ATPL written/knowledge test?
The FAA test seems way easier; you just study the Gleim which has 1650+ multiple choice questions and composed of 1,048 pages.
The EASA test which seems very difficult; you have to study the complete set of Jeppesen EASA ATPL training which is 15 manuals/books and composed of almost 3,900 pages!!
So why is there a huge difference between the study materials for the various tests?

Hello Karim. Is there some reason you have for reverting edits to the title of this question?

Just correcting spelling mistakes and making title clearer


text:
How do I know my AGL altitude while in flight?
I am about to start my PPL, still flying in my FSX.
I have a question, let's say I am flying from airport A to airport B. Both airports are in G airspace and I would like to stay in G airspace and don't go over 1200' AGL to class E. Let's say I would like to fly at 1100' AGL and keep this altitude from A to B. And let's assume we are in un-congested area, so we do not violate minimum safe altitude rule. But I do not understand if terrain in uneven, I mean its elevation is constantly changing, how do I keep my altitude 1100' AGL. I don't have radio altimeter like in Boeing. I understand that at the airport you can get your elevation, also you can have minimum safe altitude from sectional chart and also you can find any obstructions, but how do I know in a middle of my flight (if I need to).
If this question sound stupid and pilot don't fly in G airspace please let me know.

You could look out the window?  With experience, you get fairly good at judging altitude.

Why are you avoiding class E? Flying at 1200 AGL mostly is not safe (assuming fixed wing aircraft).

This is a great question! I had a job where this was a big concern for me. I was always trying to check my altitude AGL (I was usually 300-500 AGL) and used a GPS that had an approximate AGL readout based on a terrain database.

I bumped into this thread and was disappointed to see that no one was able to actually answer your question. Why you are avoiding Class E, whether 1200' AGL is unsafe, and the ins and outs of your flight planning are all subjective. After 19 months I figure you probably know the answer yourself, but I wanted to post a solution for anyone who might run into this same issue while learning to fly.
The best way that I know of to determine your en-route AGL altitude with no GPS, albeit not the most accurate, is by finding obstacles along/near your route of flight which have an MSL and AGL altitude posted on VFR sectionals. Subtract the AGL altitude from the MSL altitude of the obstacle and this will give you the MSL altitude at the ground at that location. Add to that MSL altitude your desired AGL elevation and the answer is the MSL altitude you need to be at a specific AGL altitude over that point. This method does require you to have a VFR sectional, have a generally good idea of your location (the need for accuracy of your location depends on the type of terrain you're flying over), and a bit of mental math. You also need a current altimeter setting for improved accuracy.
Anyhow, I hope this helps, for anyone in the future who might have this question and can't find the answer.

You can't know with 100% accuracy, even radio altimeters have limitations, and if you're flying on a PPL the aircraft probably wouldn't have one anyway. The VFR pilot flies with a map which shows the height of the highest terrain and noteworthy landmarks, but unless you are directly over one of these it is a matter of your experience in judging vertical distances.
I'm not sure if it's different wherever you come from, but where I fly in Australia, all airspace is measured in sea level altitudes or flight levels, never in reference to ground height, so we would never encounter your situation. Trying to stick to one height AGL might sound like a fun challenge to some but to me it sounds like less time to save my life when the engine quits.

@Michael Kjörling: Not in my experience, anyway.  As long as you don't have to clean sagebrush out of the wheel pants, at least :-)

As a practical matter, sans radio altimetry or synthetic vision, you don't have any way to determine your AGL en route accurately. Why do you want to use Class E for en route flying? In the U.S. neither Class E nor G require an ATC clearance, but both require adherence to VFR flight rules. However, the VFR daytime flight visibility for Class G is only 1 mile versus 3 miles for Class E. There's a nice table showing that at the beginning of Chapter 15
 of the FAA's Pilots Handbook of Aeronautical Knowledge.

It sounds like he's trying to avoid class E

@TomMcW I agree, but I'm curious as to why.

I guess in case you have visibility >1 but < 3 miles. I think he's really just looking for how to know how to figure out where 1200 agl is   from your altimeter msl reading

You should be able to use the Quadrental altitudes on a VNC chart. That is all you need to determine your 3000 ft AGL for direction of flight. If u are in mountainous terrain it can be quite high

The OP isn’t trying to determine how high “right altitude for direction of flight” begins; he is trying to determine an actual AGL altitude (without having a radio altimeter, which is really what he needs). This response doesn’t answer the question as asked.


text:
What happens when a temporary pilot certificate expires?
What can I do if my not-so-newly issued temporary pilot certificate is about to expire and I haven't gotten my permanent certificate yet?  Is there any way that I can keep flying while waiting for it, and is there a way to check on the status of the permanent certificate?

Please try to ensure that you are not airborne when this happens. I don't want you overhead when you suddenly cannot control your plane.

@A.I.Breveleri: Unless the expiration of his certificate causes a gun to pop out of the instrument panel and shoot the OP in the head, it probably won't be that bad.

According to this AOPA article, you can request an extension online through the FAA's Airmen On-Line Services.
You also can look up your current status here:
http://www.faa.gov/licenses_certificates/airmen_certification/new_verification_info/
In my case, this was updated about a week before my card arrived in the mail.
You can also see what date's submissions they have processed here:
http://www.faa.gov/licenses_certificates/airmen_certification

You can request an extension on just about anything issued by the FAA: certificates, registrations, etc. And if something is filled out wrong, they usually automatically renew the temp and request corrections for the official.
Don't expect anything from the FAA to arrive more than a few weeks before it expires.

The FSDO can issue you a new temporary certificate if your previous one has or is about to expire and your permanent one hasn't arrived in the mail yet.
When I got my ATP, I had to file on paper rather than through IACRA and my certificate was delayed long enough that I needed to ask an inspector to write me out a new temporary.  Took about ten minutes start to finish, the hardest part was the drive to the FSDO.

I would add that some (if not all?) FSDO's now require an appointment and you can't just "show up" to do this anymore.

This is true. I did make an appointment.

I passed my checkride on April 19th and was told by both the DPE and my instructor that typical wait times to receive the permanent certificate in the mail are around 90 days.  The DPE told me to mark the 120 expiration date of the temporary certificate on my calendar and that I should call the local FSDO if I had not received the permanent one in the mail and it was approaching two weeks from the expiration of the temporary.  The FSDO can grant 30 day extensions to your temporary certificate.
Just keep this in mind: It's is very important not to let the temporary expire since that temporary certificate "supersedes" all previous certificates.  This means you have NOTHING if a temporary Private Pilot certificate has expired and you have not yet received the permanent one.  Even your original Student Pilot certificate is no longer in effect, since it was superseded when you were issued your temporary private certificate; therefore you won't even be able to fly solo anymore.
As long as you contact your local FSDO within a couple weeks prior to the temporary certificate's expiration, you should have no problems.


text:
Is an FAA Part 121/135 checkride conducted under Part 91 or Part 121/135?
Is a checkride which is required in order to qualify a pilot for 121 or 135 operations itself conducted under Part 91 or Part 121/135 rules?
For instance, is a first class medical required in order to be PIC for the line check required by 135.299 or is only a second class medical required?  Is a fully qualified 121/135 SIC required in order to do the flight (in non-revenue service), or could it be done with an SIC qualified only for Part 91 flights?
I understand that in order to act as PIC of a Part 121/135 flight you need those, but what about for the actual checkride?

I'm sending my local FSDO (LNK FWIW) an email about this via the contact form -- hopefully I hear back by the time the bounty expires!  (Obviously, if that's not enough, we'll have to get a Chief Counsel interpretation, but that takes a while :P)

BTW -- the FSDO did respond to me, but with an "ask your carrier or POI" response.  It seems that the OpSpec-based answer from JonathanWalters is the closest we'll come to an authoritative answer unless we want to bug the Chief Counsel about this question...

@UnrecognizedFallingObject Thanks for checking!!

Any flights operated by a certificate holder must be operated in accordance with the authorization of their certificate. Authorization will vary.
An Air Carrier may conduct training1 flights under §91 if authorized to do so. If not authorized, any flights operated by that Air Carrier—including training flights—must be conducted under the part of 14 CFR (§121, §135, etc) specified by their Air Operating Certificate (AOC).

An Air Carrier may be authorized to conduct training flights under 14 CFR 91 in accordance with their Operation Specifications authorized by the FAA.
The exception to this would be if that Air Carrier's Operation Specifications do not authorize the Air Carrier to conduct flights under §91. I know of no reason for such exception, nor if any such exception has been withheld from any actual Air Carrier.
The authorization is found within the Operation Specifications of the company in question, not necessarily in 14 CFR, though it can be inferred there. See Operation Specification A001 for authorization to conduct training flights under 14 CFR 91, for example:

d. The certificate holder is authorized to conduct flights under 14 CFR Part 91 for crewmember training, maintenance tests, ferrying, re-positioning, and the carriage of company officials using the applicable authorizations in these operations specifications, without obtaining a Letter of Authorization, provided the flights are not conducted for compensation or hire and no charge of any kind is made for the conduct of the flights.

(The above is an example only; actual authorization may vary.)

An Air Carrier may also be authorized by A031 of their Ops Spec to make arrangements with an outside party for Contract Training, including instruction and evaluation. An authorized outside party under this specification may include a §142 Training Center and/or a different §119 Certificate holder authorized to conduct training and/or checking. Any training flights operated by either such certificate holder must likewise be authorized by the terms of their certificate.

1Note: Regarding the question of what is included under the definition of the term training—particularly whether checkrides are included in that definition—no explicit guidance is offered. However, a definition might well be inferred from—among other things—the definitions for the following two terms as found in Ops Spec A002, Definitions and Abbreviations:

Major Contract Training
  Any flight training, flight testing, or flight checking leading to and maintaining certification and qualification of air carrier flight crew members in accordance with the requirements (maneuvers and procedures) explicitly stated in 14 CFR Parts 61, 121, or 135; or in SFAR 58 Advanced Qualification Program (AQP), as applicable.

Outsourced Training
  Any training, testing, or checking activity which an air carrier certificate holder provides by way of a contract arrangement with another party.

Curiously enough, this specifies training, while some regulations specify training and checking. Does this exclude checkride, or are they included here as part of training?

@Lnagziger In this case, checkrides would be included under the term "training".

Do you have a reference for that?  It's curious to me that they use both phrases...

Ops Specs will sometimes use the term "training flight" to encompass training, evaluation, and checking flights, though sometimes each are differentiated for clarity, particularly when authority is granted to outside parties to perform one or more of each. See Ops Spec A031 "Contract Training" for an example of both phenomenon.

@Lnafziger See my edit here adding support for checking to be included under the definition of "training".

You're asking a couple of different questions here, I think.
Neither FSIMS nor the FARs specify whether a particular checkride flight must be conducted under part 91 or 135/121.  Regarding medical certificates, FSIMS 5-887 indicates that for ATP 121/135 applicants:

CREW QUALIFICATIONS. The crew, with the exception of the applicant, must be qualified and current. [emphasis added]

As for checkrides, they're part 61..  So as to the part of your question that asks about what medical you need during a checkride, FAR 61.23(a)(3) says that you need at least a 3rd class medical.
That said, FSIMS guidance for examiners conducting 121/135 checks occasionally makes reference to "limitations as specified by the certificate holder's operating manual".  Since this wouldn't make sense if the flight was conducted under part 91, I suspect that:

There is no defined answer to your question
The flight that a checkride happens during is conducted according to whichever rules would otherwise apply
Checkride flights are just special that way

A flight isn't conducted under Part 61....  I wonder if the FAA had issued any letter of interpretation covering this.

@Lnafziger - obviously. I'll edit the question to make what I'm trying to say more clear.


text:
Can a non-instrument rated safety pilot log PIC during an IFR flight?
The Scenario:
An instrument-rated private pilot files and flies IFR while accompanied by a non-instrument-rated private pilot who is otherwise fully certified and endorsed to act as PIC in that aircraft under VFR flight rules. While in VMC, the instrument rated pilot uses a view limiting device in order to practice IFR scan and procedures towards maintaining currency, while the other pilot acts as safety pilot. Both pilots meet all medical and currency requirements for the flight.
The Question:
Can the safety pilot in the previous scenario log as PIC that time during which he/she acted as safety pilot?
Note: This question differs from the question, How should time as safety pilot be logged?. This question is not answered there; this question concerns whether or not a non-instrument-rated pilot is qualified as required crew during simulated instrument flight in VMC while operating on an IFR flight plan, and whether that pilot is qualified to act as PIC in the given scenario.

"A safety pilot does not have to have an instrument rating if the flight is being conducted under the visual flight rules. However, if the aircraft is operated under instrument flight rules, even in VFR conditions, whoever is acting as pilot in command of the flight must hold an instrument rating appropriate to the aircraft being operated" Source

So I believe that if you are on an IFR flight plan, a VFR pilot cannot act as a safety pilot since you would be operating under IFR in VFR.

@RonBeyer, the AOPA article you quote goes on to say, "If the pilot under the hood is instrument rated and acting as pilot in command, even though the flight is IFR, the safety pilot is not required to have an instrument rating or be instrument current." I think the answer is that the non-instrument rated pilot can act as safety pilot, but not as pilot in command, and therefore cannot log pilot in command time.

I don't see how this can be a duplicate; the other question is specifically about VFR and this one is about IFR.

As safety pilot is not a required crew member under IFR, but is under VFR

@rbp Actually, a safety pilot is required if operating under VMC and the PIC is using a view limiting device (at any time).  It doesn't matter if it is operated under IFR or VFR rules.

@Lnafziger yes, i should have written: A safety pilot is not a required crew member, except when the pilot is using a view-limiting device in simulated instrument conditions.

No
The way that both pilots can log PIC is that the pilot using a view limiting device is logging PIC as sole manipulator and the safety pilot is logging PIC because he is acting PIC and a required crew member.
If the flight is operating under an instrument clearance then the acting PIC must be instrument rated. If only the pilot with the view limiting device is rated then he is acting PIC and is the only one eligible to log PIC. The safety pilot is also not allowed to log SIC as a required crewmember without an instrument rating while operating under IFR.
If you are in actual IMC then you shouldn't be logging anything and they other guy shouldn't be wearing a view limiting device.
If you want the PIC time ask your friend to fly VFR or get yourself an instrument rating.

@JonathanWalters 91.109 requires the safety pilot needs to have category and class ratings appropriate for the airplane. Id consider this a bit vague in arguing no instrument rating is required for safety pilots under IFR but id hope to find a legal interpretation out there before making such an argument.

This answer is correct in that the safety pilot can't log acting PIC time (which was the specific question), but he can log PIC as the sole manipulator if he takes the controls. And interestingly, in actual IMC if the safety pilot takes the controls then he can log PIC but the rated pilot can't. Legal interpretation here.

What prevents the safety pilot without an instrument rating from logging SIC while operating IFR?  If they are in VMC conditions and the PIC is using a view limiting device, then he is a required crew member...  Other than that statement, I agree with this answer.

@Lnafziger if the flight is operated under IFR (as the question assumes), 61.51(f)(2) requires an instrument rating to log SIC if the flight requires an instrument rating, which it does if the PIC accepted an IFR clearance..

What happens if both Pilot A and Pilot B are instrument rated? Pilot A wants to be under the hood to practice in an IFR flight and Pilot B is the safety pilot. Does the rule of safety pilot also logging PIC time still apply?

This answer is just wrong. Period.  Well, except that someone can't fly simulated instrument while in actual instrument conditions. That's sort of a no-brainer.

"If only the pilot with the view limiting device is [instrument] rated then he is acting PIC and is the only one eligible to log PIC."  <-- Wrong.

This AOPA article says: "If the pilot under the hood is instrument rated and acting as pilot in command, even though the flight is IFR, the safety pilot is not required to have an instrument rating or be instrument current." <-- Correct

@RyanMortensen - Although you and AOPA are correct in saying that the safety pilot in this situation isn't required to have an instrument rating, that has nothing to do with whether or not the safety pilot is eligible to log PIC.

@SteveV. you are absolutely correct, sir!  They are two separate matters, but my interpretation of 61.51(e)(1)(iii) leads me to believe it could be logged because the regulations under which the flight is conducted would thus require a safety pilot.  I am not a lawyer though.  I'm open to the possibility of being wrong, but if I am, then anyone who ever says safety pilots can log PIC under any circumstances, are also wrong.  Are you saying this is an urban myth?

The safety pilot can't log any acting PIC time but he could still log PIC time as sole manipulator of the controls (if he ever takes the controls, that is).
That's from an FAA legal interpretation (based on this previous one) that clarifies logging PIC time under IFR without an instrument rating. The interpretation discusses an instrument-rated pilot ("Pilot A") flying with a non-instrument-rated pilot ("Pilot B").
First, acting as PIC and logging PIC are different things, and only Pilot A can act as PIC under IFR:

The FAA has previously stated that there is a distinction between logging PIC time and acting as a PIC. See Herman Interpretation. To act as a PIC (i.e., the pilot who has final authority and responsibility for the operation and safety of the flight), a pilot must be properly rated in the aircraft and be properly rated and authorized to conduct the flight. In your example of an IFR flight, being properly rated and authorized would include having an instrument rating. Accordingly, only Pilot A may act as the PIC, and Pilot A has final authority and responsibility for the safety of the flight regardless of who is manipulating the controls.

But you don't need an instrument rating to log PIC time, as long as you're rated for the aircraft. That means that in simulated instrument conditions the safety pilot ("Pilot B") can't log any time as acting PIC under 61.51(e)(iii) but he can still log PIC time if he's the sole manipulator of the controls, under 61.51(e)(i):

for the purpose of logging PIC time under §61.51(e), a pilot must hold ratings for the aircraft rather than for the conditions of flight. Accordingly, Pilot B may log PIC time for the portion of the flight during which Pilot B was the sole manipulator of the controls.

In other words, Pilot A can log PIC time for the entire flight but Pilot B can log it only for the time spent as sole manipulator. If Pilot B never touches the controls then he can't log any PIC time at all.
In actual IMC, 61.51(e)(iii) doesn't apply because a safety pilot is only required in simulated IMC. The FAA's conclusion is that if Pilot B takes the controls in actual IMC then he can log both PIC and instrument time, but Pilot A can't log anything:

Pilots A and B are flying in actual IMC conditions, not simulated instrument flight conditions, and the aircraft operation is not one for which "more than one pilot is required under ... the regulations under which the flight is conducted."  Speranza Interpretation (Dec. 4, 2009). Therefore, Pilot A is not acting as a safety pilot and, as was the case in the Speranza Interpretation, being the PIC in this context is not a basis for Pilot A to log flight time under § 61.51 for the portion of the flight being logged by Pilot B as PIC flight time while the sole manipulator of the controls.

Pilot A is still acting as PIC in that case, he just can't log the time.
Finally, remember that the FAA interpretation is only about the legality of logging PIC time under IFR. Unless you're a CFII, letting someone without an instrument rating fly under IFR would be very risky, even in VMC. There's a good chance that if something went wrong then the FAA would go after both pilots on the basis of 91.13 (careless and reckless operation).

no pilot logs "acting PIC" time. "acting PIC" is a role. "logging PIC" is an administrative function.

@rbp 61.51(e)(1)(iii) says that you can log PIC "When the pilot [...] acts as pilot in command..." if more than one pilot is required for the flight. Acting PIC is indeed a role, and being in that role on a flight requiring more than one pilot is one possible reason for logging PIC time.

glad you agree!

@RBP Lots of pilots, and more importantly, hiring companies differentiate between Flight Time spent as the acting PIC vs Flight Time that was loggable as PIC time. The former is more restrictive and valuable; the latter is often discounted, especially—as I understand—by the airline industry. For example, I flew BE-20 as a required crewmember and was able to log SMoTC time as PIC time. This time is not recognized by lots of hiring companies as true PIC time. My logbook has columns for Acting PIC time and for PIC time loggable under §61. The difference can be useful.

The issue for me is 91.109(c)

No person may operate a civil aircraft in simulated instrument flight unless—

The word simulated seems to me that while on an IFR flight plan the flight isn't simulated hence there is no need for a safety pilot.  As a result, the other pilot irregardless of whether or not they are capable of acting as the legal pilot in command cannot log PIC time.
They are not a required crew member so they cannot log SIC time either.
While in VMC conditions on an IFR flight plan it is prudent for all pilots to see and avoid other aircraft.  If one is wearing a view limiting device, the other pilot is still not required due to being on an IFR flight plan.

IFR refers to flight rules not meteorological conditions. IFR flight can be conducted in VMC or IMC and that may be further separated into simulated IMC and actual IMC. So yes, you can fly under instrument flight rules in simulated instrument meteorological conditions if you have a safety pilot. You always need a safety pilot if you have a view limiting device (even under IFR) as you are still responsible to see and avoid while visibility allows (e.g. VMC or simulated IMC)

Also if you are wearing a view limiting device a safety pilot is a required crew member and if properly rated may log SIC or even PIC if both pilots agree the safety pilot is the acting PIC.


text:
Do the FAA's InFO publications carry any regulatory or legal weight?
The FAA publishes Information for Operators documents giving:

valuable information for operators that should help them meet certain
  administrative, regulatory, or operational requirements with
  relatively low urgency or impact on safety.

Some of these documents seem to offer interpretations on regulatory matters, and are sometimes cited as such. In some cases, these interpretations may provide permission to operate more freely. However, I could imagine that in the case of others, the interpretations may prove to be more restrictive and burdensome than a plain reading of the regulations.
What regulatory or legal weight do do these InFO publications carry, if any?
Since these notices are directed at certified operators, does the answer vary depending on the audience?

I don't think they carry any regulatory weight, they are not themselves regulations. As for the interpretations, if they are written by the FAA then they could be used in court to argue in favor of somebody who used that interpretation since it was written in a published manner. However if it is not written by an authorized person at the FAA, then it may not hold up in court. This may be a better question on law.se.

An InFO (Information For Operators) document is an informational document containing recommendations. Quoting directly from FAA Order 8000.91:

Much like a Safety Alert for Operators (SAFO), which contains critical safety information, an Information for Operators (INFO) message contains valuable information for operators that should help them meet administrative requirements or certain regulatory requirements with relatively low urgency or impact in safety. INFOs contain information or a combination of information and recommended action to be taken by the respective operators identified in each individual INFO.

They are not regulatory changes/obligations (like ADs) or formal notices of violation (administrative actions) - they're just a "friendly hint" that the FAA is concerned about something and would like operators to be aware of it and take action if the operator's analysis determines it to be necessary.
If the situation addressed in an InFO or SAFO document doesn't improve it may wind up prompting a regulatory change.
The InFO and SAFO programs are very similar, so FAA Order 8000.87A covering the SAFO program may also be of interest.

Note that while the actions and recommendations identified in a SAFO or INFO document are voluntary their legal weight goes beyond what's provided for in the regulations: If an operator receives a SAFO or INFO notice that's applicable to their operation and ignores the recommendations they may leave themselves open to civil action (negligence or the like) if something goes wrong. Consult your attorney before shredding, etc.


text:
Is a VHF NAV receiver inherently capable of processing a LOC signal?
These last few weeks I have been flying a couple of different aircraft that had inoperative glideslope capabilities, but I was able to fly LOC approaches without trouble. In my career as a pilot and mechanic, I have always had the—possibly inaccurate—understanding that a VHF NAV receiver had the capability of receiving and processing both VOR and LOC signals.
My question is prompted by this answer to a question regarding flight plan equipment codes—and particularly the comment section of that answer. In the comments of that answer it was stated that an ILS capable VHF NAV receiver is necessary to fly a LOC approach. For the purpose of this question let's overlook the inaccuracy of the ILS part of that statement and instead consider the LOC capabilities of a VHF NAV receiver.
I understand that the additional requirements needed for ILS capability include a glideslope antenna (possibly included in the existing NAV antenna), equipment to process the frequency pairing, and a glideslope display. I know that all LOC frequencies fall within the range of VOR frequencies (108.10–111.95 MHz and 108.0–117.95 MHz respectively) and the frequency spacing is compatible. I also understand that the circuitry required for VOR signal processing includes circuitry not required for LOC signal processing (that circuitry which can deteriorate over time requiring the periodic VOR accuracy checks).
Given all this, my questions are:

Is LOC signal processing an inherent capability of a NAV receiver: Will any given VHF NAV radio receiver be inherently capable of processing a LOC signal, or is there additional circuitry required for that capability beyond that required for VOR signal processing?

And if not,

Are there NAV receivers incapable of LOC signal processing: If LOC signal processing is not an inherent capability of a VHF NAV receiver, are there NAV receivers that were built without the LOC signal processing capability? In other words, is it possible that a pilot or mechanic would encounter a NAV receiver that did not have LOC signal processing capability? More precisely—from a pilot's standpoint—might I encounter a NAV radio that I could use to navigate tuned to a VOR station but not a LOC station?

Any VHF radio can receive the carrier signal of a LOC signal but to use it, you need dedicated circuitry.
The LOC transmitter transmits the carrier wave, frequency modulated with two side lobes of 90Hz and 150Hz.  In order to use the LOC signal, circuitry needs to exist which will filter out the 90 and 150Hz then measure the difference between them to determine where in the beam the receiver is located.
This circuitry is dedicated to the ILS receiver.
It's a similar story for GS which simply uses lobes above each other, rather than left and right.
So

Is LOC signal processing an inherent capability of a NAV receiver

No.

Are there NAV receivers incapable of LOC signal processing.

Yes.  All of them which do not have an ILS function (e.g. the Rockwell Collins VOR-900).
[ BEGIN Mythbusters Territory]
I've just tuned my hand held airband receiver to the ILS of my local airport.  I think I can make out the beat frequencies from the 90 and 150Hz although I doubt that the low pass filter is letting much 90Hz through.  I guess it's optimised for voice reception so probably cuts off at about 100 or 120Hz.
The next time I drive past the end of the runway, I'm going to test whether I can detect any change in the beat frequencies as I drive through the lobes.  There is a convenient hill about a mile from the threshold which will put me a couple of hundred feet above so I should be in the beam.
I guess it might just be plausible to hear when you are going left and right of the centre line.
I'll report back.
[END Mythbusters Territory]

Thank you. Can you provide an example of a NAV receiver incapable of LOC signal processing?

@JonathanWalters I'm not sure what you are asking since any nav radio that does not have an ILS capability is, by definition, incapable of processing a LOC signal.  Here is just one example, out of hundreds.

That's exactly what I am asking. Your answer showed that such a receiver might exist in theory; as I asked in my question (though perhaps not clearly) I wanted to know if such a LOC-incapable receiver existed in actuality. And you answered that; thank you.

Your Mythbusting may just prove that it's plausible that one could, in a Horribly Desperate Situation ™, execute an ILS landing with a standard audio radio. Of course a Good Pilot™ would never get him/herself into said horribly desperate situation.

@FreeMan I like the TMs :)

@FreeMan Yes, except I would think only a LOC approach, not an ILS. My VHF handheld does not cover the frequencies for glideslopes.

@Simon thank you sir. Google search to the rescue! Also, helps ensure others know that this is a more lighthearted comment.

@JonathanWalters. Yeah... Not a pilot. Still coming to grips with the differences. My bad.

@FreeMan No worries! I like your idea :)

@JonathanWalters.  To continue with the "myth plausible" theme, I supposed I could have a VHF receiver to one ear and a UHF receiver to the other :)

@Simon While in the soup partial panel :) Horribly Desperate Situation™ indeed!

From what I understand, back when approaches were first being designed, they did indeed just listen to the audio and as they moved back and forth it would change to a solid tone where the two signals met, but modulate at different audible pitches depending on whether you were left or right of course.

@Lnafziger You seem to be describing the Lorenz beam system, though the modulation was dots/dashes (one- or seven-eighths of a second per second) rather than in pitch.

@JeffreyBosboom Very possible as I was just trying to remember something that I was told, and don't have an actual referencereference!

@Simon Still waiting for that report ;) Did you discover anything? I now live near an airport where this test would probably be possible; perhaps I will have to try it myself.


text:
Is the Diamond DA62 pressurized?
In a recent conversation about the Diamond DA62 I was speaking with someone who thought the aircraft was pressurized. I was shocked considering the door design. Shocked to the point of disbelief. A quick Google search referencing the following page seemed to prove that  it was indeed pressurized.

Yes, the DA62 is pressurized. The aircraft features a baseline cabin pressure altitude of up to 8,000 ft at the specified maximum operating altitude (28,000 ft). This helps to reduce fatigue during long flights, and make the experience of flying more comfortable for passengers.
https://www.newzealandrabbitclub.net/is-the-da62-pressurized/

Hard to believe! I tried and found no reference to it's differential pressure limits or operation of its pressurization system. There are videos of pilots wearing cannulas above 10,000 feet.
So, is the Diamond DA62 pressurized or not?

Diamond's own website says the DA62's service ceiling is 20,000 ft, which contradicts the New Zealand Rabbit Breeder website you cited... and that makes me somewhat suspicious that the New Zealand Rabbit Club is not the foremost authority on the details of the DA62...

They also claim that the DA 62 "is not turbocharged" but according to the official fact sheet (pdf) by Austro Engine, the AE300 are indeed turbocharged. They also say that "The engines are mounted in the rear of the aircraft’s fuselage and do not use a piston"... I'd just forget that site...

It feels to me like the "New Zealand Rabbit Club" page about... aircraft.... is written by AI for the sole purpose of generating clicks in response to Google searches

There's nothing that inherently prevents those swing-out doors from being used pressurized if the mechanism was beefed up a bit. Compare the doors on the Piper Meridian and all the regional jets and turboprops with integral airstairs, particularly the E145 which doesn't use piano hinges.

What does the New Zealand Rabbit Club have to do with airplanes?

I'm 99% sure I know the original source of that quote now. Me: "Is the DA62 pressurized?" ChatGPT: "Yes, the Diamond DA62 is a pressurized aircraft. It is a twin-engine light aircraft manufactured by Diamond Aircraft Industries. The pressurization system allows the cabin to be maintained at a higher atmospheric pressure than the outside environment, providing a comfortable and controlled environment for the occupants during flight. The pressurization system helps to reduce the effects of altitude, such as hypoxia, and allows for more efficient and comfortable high-altitude operations."

@Someone-OnStrike - I guess that according to the current site policy, I have to tell you not to answer in comments but instead post it as a real answer! (please don't)

As a Kiwi, I can confirm that website doesn't even know rabbits, let alone airplanes.   Heck - even Wikipedia knows that the "New Zealand" rabbit breed is from California.  It is clearly a pile of scripted twaddle that doesn't belong on the web.  "do your research" means more than one source, ideally independent sources.

@Ben this particular page format is a dead giveaway of an AI-generated website intended to harvest views for ads. Search almost any topic now and you'll see at least one or two pages with the exact same layout and very similar writing style.

No, neither the DA 62 nor the DA-50RG are pressurized, though they do have an integral supplemental oxygen systems onboard.  I have no idea where the New Zealand Rabbit Club(?) came up with that, but they are misinformed.
What appears to be going on is that they are confusing cabin pressurization with critical altitude on the turbos. The DA 62 does have a critical altitude somewhere in the neighborhood of 12 to 14,000 feet MSL and a maximum operating pressure altitude of 20,000 ft.  This is very different than a cabin altitude.  The video also features a Piper PA-46 Meridian, which is, in fact, pressurized, so I don’t know if they are confusing the two aircraft.  In fact, the quoted 8000 foot cabin altitude at FL280 sounds about right for a non-RVSM certificated Meridian.

Me: "Is the DA62 pressurized?" ChatGPT: "Yes, the Diamond DA62 is a pressurized aircraft. It is a twin-engine light aircraft manufactured by Diamond Aircraft Industries. The pressurization system allows the cabin to be maintained at a higher atmospheric pressure than the outside environment, providing a comfortable and controlled environment for the occupants during flight. The pressurization system helps to reduce the effects of altitude, such as hypoxia, and allows for more efficient and comfortable high-altitude operations."

AI just ain’t that intelligent, is it?

Having experience on the DA-42, I would also have concerns on how the 62 would be able to pressurize properly. The doors on it are pretty large and don't really have a good edge seal or a good locking mechanism for pressurization. There is also the little windows on both pilot side windows that pop open pretty easily already with no pressurization.

@CarloFelicione It's a lot of A, but not much I.

I have a new DA62 and it definitely has NO Pressurization whatsoever.
Do not trust answers from an AI or random website. If you have to know something for sure, contact the factory or a certified dealer.

We do not accept AI-generated answers, and hopefully we're not a "random website". Our answers are often cited with reputable sources. Take the [tour] and, can I say Welcome to Aviation Stack Exchange.

@Jamiec, what do you mean he's calling this site AI generated and a random website? I think he's telling to not to listen to AI (which is mentioned in the previous answers) and not to trust the wrong website that the original question has mentioned. This is a correct and accurate answer.

I think the references to AI and random websites is simply a critique of what's cited in the OP question. And I agree that owning a DA62 is adequate credibility to state that the aircraft is unpressurized.

@AadirajAnil No, comments on a previous answer mention AI, but the answer does not. Thats exactly why pseudo answers in comments are not OK. I don't dispute this answer is right, but it adds nothing to the existing answers which are also right, but with something more than a simple "no". ALso I think you misunderstood my comment. I said we dont accept AI generated answers, not that this is an AI generated site... whatever that means.

There is also no proof that the author of this post actually owns the aircraft i.e., the post is unreferenced. I could post that I have the aircraft and it is pressurized, and that would bear the same weight. (I actually think the answer is correct, but a reference would be nice). A link to the flight manual was provided in the earlier answer.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
What is P-Factor in Propeller Aerodynamics?
What is the P-Factor when we're talking about a Propeller Aerodynamics ?
Thanks

Actually I didn't get an answer from that topic ! It's the reason why I posted this specific one concerning the propeller !

I agree that the answers to the other question don't really explain what the P-factor is but, still, your question is essentially identical to the other one. Rather than repeating the question, which fragments the answers, it would be better to comment on the existing answers asking for improvements, ask in chat to try to encourage new answers, or even post a bounty on the existing question.

It seems the other question has a good explanation of what is the P-factor. When the pitch is increased, the aircraft has a tendency to yaw to the left if using a clockwise turning propeller (right hand). The pilot needs to compensate this asymmetric thrust. On helicopter this effect is compensated by the cyclic swashplate, the pilot has nothing to do. When turning this compensation is altered, the P-factor asymmetry is used to perform the turn.

If the airflow is parallel to the axis of rotation of a propeller, the resulting thrust force will also be parallel to the axis of rotation and act on the center of the propeller disc.
If, however, the airflow hits the propeller at an angle of less than 90°, the resulting force will tilt towards the flow direction and shift away from the center of the propeller disc in a direction orthogonal to the directional change.
Example: You fly in a single-engined plane, the two-bladed prop is spinning clockwise when seen from the pilot's view and you push the left pedal such that the aircraft flies in a sideslip. If both propeller blades are level, nothing much changes, but if the propeller turns another 90°, both blades will see very different flow conditions (see the sketch below):

For the upper blade, which moves from left to right, the sum of circumferential speed ($\omega\cdot r_{Prop}$, red) and air speed ($v_{\infty}$, blue) is bigger than that of the lower blade (black arrows) and hits the blade at a larger effective angle of attack $\alpha_{eff}$. Thus, the lift force created by the upper blade is much bigger, and as a result it will act at a point on the upper half of the propeller disc.
The same happens when the plane flies at a high angle of attack and high power (ground run of a taildragger, or climb) and the airflow hits the propeller disc slightly from below. Now the thrust force will move to the right and tilt slightly downward. This will cause the aircraft to  turn to the left and must be compensated with right rudder.
This effect is sometimes called p-factor, but this is not a factor in an equation, but something you need to factor in when flying at high angle of attack. Note that the rotational component of the prop wash will cause a similar effect when it hits the rudder at an angle, adding to the leftward tendency of the plane.

P factor stems from the fact that the downward side of a propellor generates more thrust than the upward side (because of the helix like nature of the air flow). This manifests its self in a leftward tendency for American made engines, it should be noted that not all engines rotate the same way and its not uniformly a leftward tendency.  This causes the plane to yaw to the left under high power and high angle of attack situations.
This is mainly prevalent in single engine prop planes. Twin engine planes (at least modern ones) tend to implement counter rotating propellors to counteract this. Older twins that have props rotating the same way have a critical engine

This answer describes prop wash, but p-factor is a different thing altogether.


text:
How to locate the owner of a 5' styrofoam wing found in a field?
I found a 4-5' styrofoam wing in eastern Montana in a field. It has what looks like a registration number on it. How can I trace that number to try to return it?

Any possibility of getting a photo and adding it here?

Pure styrofoam, or styrofoam core with something else around? Can you please be more detailed?

If it's from an R/C plane, which seems likely, there's a chance it could have an Academy of Model Aeronautics (AMA) member number on it somewhere.

If it has a US registration number on it (N followed by 1-5 numbers or letters) you can search the FAA registration database to find out what aircraft has that particular registration number, and who owns it.
In the case of a 4-5 foot styrofoam wing this would likely only be useful if the aircraft in question was a registered UAV.
Some common sense needs to prevail here: Model aircraft often have an N number painted on them for decorative reasons, so if you look up N12345 and it says "That belongs to a Piper Cub" you can safely assume this wing does not belong to that particular real-world aircraft (as the Cub's wings are not made from styrofoam, and are more than 5 feet long).


text:
How are ADS-B surface position frames decoded?
I am developing C# code that reads 1090ES Automatic Dependent Surveillance - Broadcast  (ADS-B).
The ADS-B position messages broadcast by the aircraft's ADS-B transmitter have a different encoding depending on whether the aircraft is airborne or on the ground.
When I decode Airborne Position frames as Compact Position Reporting (CPR) encoded positions, I get realistic results. However, when I decode the CPR for Surface Position frames, the positions I get are far (geographically) from what I should get.
How is the CPR in Surface position messages different from airborne position messages and how are they decoded properly?

Too high a value for what parameters?

Sorry, it was wrong to write "too high value", I edited " much too far position from what I should get". Now I've just found out of some C# library that there may be differences in computations of Surface/Airbone frame types.

Why is this put "off-topic". Ads-B is a standard positioning system in aviation. The site even has a tag for it.

As I see it, it is actually both software and aviation.

If you see it clearer, yes it's OK that you re-write the question. I guess I'll have a validation step, not sure, it happens some times. But OK.

@TTT I've rewritten it but I don't think you get the validation step since my rep count is high enough for the system to trust me. Nevertheless, please check and change the wording as you see fit.

Thank you. I just changed the first line because. Not extremely important but, though my C# code decodes Ads-B frames, I'm not literally writing a "decoder".

The Compact Position Report (CPR) coding in Surface squiters is different from Airborne CPR coding. The resolution is 4 times better (~1.25 m instead of ~ 5 m), at the cost of losing the 2 most significant bits.
Due to this, global surface position decoding gives an ambiguous solution. IIRC the solution can be at 4 points on the globe, you have to select the nearest to you. And you should validate that it is within a realistic range, like you should do with Airborne CPR decoding. After you validated the position using global decoding on a couple of odd- even squiter pairs you can use the more efficient local decoding. Of course, as with Airborne CPR decoding, you need to protect against position jumps and time gaps in your decoding algorithm.

You mean I should do 4 "local" CPR decodings and pick the one that is closest to my reference poin? What are those points ? Context: I'm working within a range of max a few handred kilometer from some reference point.
I don't really know how to do local CPR decodings ? So far the only CPR decoding I know is inspired from https://inst.eecs.berkeley.edu/~ee123/sp15/lab/lab2/rtadsb.py

Maybe I could get inpiration from this  https://github.com/bistromath/gr-air-modes/blob/master/python/cpr.py , function cpr_resolve_local with my reference location. Is that what I should do ? (Implementing this in my C# solution may take some time, so I'd prefer to be sure I'm on the right way.)

You could look in RTCA DO-260B or EUROCAE ED-102A, appendix A 1.7 and appendix T. See also this question. I'd like to write a more detailed explanation if I find the time, but don't expect that to be soon.

Ah, thank you.  I suggested colleagues we buy DO-260B. But so far they prefer to rely on Google searches...

If you are trying to build anything serious, I strongly recommend buying DO-260B or ED-102A (they are effectively the same, pick the cheapest).


text:
How does compressibility affect the critical angle of attack?
Why does the critical angle of attack reduce with increasing mach number or What is the effect of compressibility on critical angle of attack?

First, I have to define what the critical angle of attack is:
When an aerodynamicist speaks of critical conditions, he or she means the condition when the speed of sound is reached locally. The critical Mach number is the speed, measured in multiples of the speed of sound, when the top local speed in a flow field equals the speed of sound.
The critical angle of attack is the one when the local flow speed first reaches the speed of sound. Since it depends on the initial flow speed, it is only valid for a given flight speed.
Two parameters are responsible for the local increase in speed: Thickness and angle of attack. A body needs to displace air, so the air will squeeze around it, speeding up in the process (or slowing down in fully supersonic flow).
When the angle of attack is increased, the stagnation point moves below the airfoil nose so the air flowing over the top of the wing needs to negotiate its leading edge first. This speeds it up and leads to a suction peak. Another view of the same phenomenon is that increasing suction on the upper side of the airfoil will accelerate the air flowing towards it.
With a higher flight speed, less local flow acceleration can be tolerated before the critical conditions are reached. There is even a maximum speed in that suction region of high local curvature that will not be exceeded in subsonic flight and which limits the maximum possible lift coefficient. Higher flight speed leaves less margin, so the angle of attack for maximum lift is reduced with increasing flight speed.
If by critical angle of attack you mean the one where maximum lift is reached (conventionally called stall angle of attack), please read here how it can be influenced. Depending on the flight Mach number, flight speed should be increased or decreased to maximize it.

I believe that the question was not regarding the angle at which the flow reaches supersonic speed but as the angle at which the maximum $C_L$ starts to decrease. Why the "conventional" critical angle of attack in "$C_L$-$\alpha$" graph starts to decreases with Mach number, and I would like to add the sub-question, why the gradient of the same graph increases with the Mach number?

@Darjan So why did the question not ask for it directly? We use standards in terminology for a reason and questions can be edited. Besides, your sub-question deserves its own question here. And why did you feel the need to downvote instead of improving the answer? This is odd.

Thank you for the reply, I will post that question later today. I downvoted it because I thought that the answer was not satisfactory. I see that you edited the question with regard to the "conventional" angle of attack, so I will cancel my downvote.


text:
How does a true airspeed indicator work?
How does a True Airspeed Indicator work?
I am aware of how the air speed indicator works, but how is the density input being provided to this instrument?

This answer contains some math and background on how TAS can be calculated/displayed that might be helpful.

For a basic True Airspeed Indicator (TAS Meter) like the one shown below, you simply dial your pressure altitude into the top window using the knob (aligning it with the appropriate temperature mark at the bottom of that window), and then read your true airspeed in the other window at the bottom.

Your pressure altitude can be obtained by setting your altimeter to 29.92 and reading the indication, the air temperature can be obtained from an outside air temperature (OAT) gauge (or you can use one from the Winds Aloft forecast if your aircraft does not have an OAT gauge), and the combination of the two gives you your density altitude.
The meter itself is simply a mechanical slide rule, performing the same functions as you could do manually on an E6B flight computer.
The indicator above is showing a true airspeed of about 202 MPH, at a pressure altitude of 10,000 feet and a temperature of -15 degrees.

For a nice video tutorial check out this one from the University of Oklahoma.

So TAS is in knots not M.P.H? Does the label "TRUE SPEED KNOTS" mean that white scale is in KNOTS? What a confusing indicator! I hope ones without MPH are available...

@Andrius That was a typo in my answer, but it depends on the instrument: in this illustration TAS is in MPH (the outer scale is MPH, and the true airspeed arc is on the outer scale). There are also indicators that only display knots, or that have knots on the outer scale & MPH on the inner scale. (I've never seen one, but I suppose its possible to have a design with both scales on the TAS arc as well, the correspondence between the two is linear...)

@voretaq7, the picture has a slight problem that it does not indicate which are the separately moving components well. The white windows clearly are, but apparently the inner scale should be as well and there is absolutely no indication of that in the image.

@JanHudec The inner scale does not move in the unit illustrated, it's fixed and will always display indicated airspeed in knots. I've replaced the image with a better one that makes this easier to see (also from Wikimedia Commons - the generic "airspeed indicator" ironically had a better image than the "true airspeed indicator")

@voretaq7, ok, now I see. The labels are rather confusing though. Because the inner scale is indicated speed in knots, but the label closest to it says "true speed knots". The main ,outer, scale is, somewhat unexpectedly, in mph. And only the white scale is actually true airspeed (in mph again).


text:
What is the best way to retrieve (and transmit) location (GPS) of plane in real time?
What are some of the best ways to retrieve and transmit the location of a plane I am in, real time.
To speak in realistic terms, I'm currently training for my private pilot's license and as such am spending a lot of time in various planes I do not own / have decision powers over. How could I share my current location with someone in a remote location while in the air without physically modifying the aircraft.
There are a couple of ideas that have come to mind, but my understand of the solutions or challenges are not complete:

There are websites like flightradar24.com, but the aircraft I'm in often don't show up. That being said, a flight I took yesterday DID show up, but was not terribly accurate. Perhaps that is because I filed a flight plan and / or used flight following (which would put me on the radar tied to my tail number).
I could use a simple app like "Find my Friends" on the iPhone. I realize this is crude, but it could work. That being said, I don't know how well cell phones transmit above the ground.
Some other portable device. That device would need to transmit real time in some way and there would need to be some way to look up that transmission.

Any information on this would be appreciated!
UPDATE:
I'm talking about general aviation here. Speeds <= 120 kts altitude typically <=  5,500

@mins he's talking about GA, which at the altitude that he's likely to fly at and the lower speeds, cellular services are not usually a problem. Lots of headsets have Bluetooth just for that purpose, music and voice calls.

Hi @RonBeyer, you're correct - I am referring to GA. I am unaware of whether or not cellular service works above ground. My understanding is cellular signals transmit horizontally and have very little vertical reach which is where my concern would be around that. Is that true, or is a phone perfectly usable in flight? I've never checked while flying for the obvious reasons.

If you are wanting to share for safety reasons, look into personal locator beacons. Sportys sells them as well as other retailers.

I've never had an issue flying in my area getting a signal less than 6000 ft at least.

The thing of FR24.com not showing your planes is that the planes you are in don't have ADS-B transponders.

I'm curious as to why you want to share your location real time. Is it so your wife/friends can watch your progress? Just in case your CFI tries to kidnap you? In case you crash you want to be found quickly? What you're trying to accomplish by making this info available may help shape the answers you get, and point you more quickly to an appropriate solution.

Hi @FreeMan, it is most definitely because I'm afraid that my CFI is going to 'nab me. ;) In all seriousness, it is just because I thought it might be neat to be able to share my location with the wife and take a look at my route after the fact. Basically, it's just for fun and because I have that type of curiosity.

Use of a cell phone in flight generally violates FCC regulations and can violate FAA regulations as well based on determinations of the operator.  While, some people do violate these regulations, you should at least consider this, and discuss it with your CFI.  Here is one related article about these regulations:  http://www.capmembers.com/emergency_services/operations_support/cellphone-and-data-card-use/

Also see this question and this question.

There are a few consumer-facing easy-to-obtain devices that you could use for this, although they don't quite transmit in real-time (they'll transmit updates down to every 2 minutes).  Spot and inReach are aimed at more casual users, and Spidertracks offers real-time tracking that might be considered targeting more of the commercial or "prosumer" market, but they still transmit updates every 1-2 minutes.
They all work in a similar fashion: rather than some kind of ground-based radar, they utilize a combination of GPS to calculate your location and use the Iridium Satellite communications network to transmit it (so it doesn't rely on cellular signals and has global coverage), they transmit on an interval you decide to a website that your interested party could monitor.  This is the key difference from other answers that use an app on a device: even if the app is linked to a real-time tracking service like Map my Tracks, your phone or tablet will still be relying on the cellular network (which you're technically not supposed to be using in flight), and even if it does work, it could be intermittent. These devices link into the Iridium Satellite network for global coverage.
The three devices are: Spot Satellite Communicator and the DeLorme (now owned by Garmin) inReach, and Spidertracks.
This isn't a free service, there is a monthly fee for using the devices.
Spot is around USD$150
inReach is around USD$350
Spidertracks start at USD$1000
In July 2016 ($USD)
inReach: Allows tracking updates every 10+ minutes ($15/month) or the 99/month package allows for updates every 2+ minutes.
Spot: 50/year allows 5, 10, 15... minute tracking update intervals or $150/year: 2.5+ minute tracking updates.
Spidertracks has various plans, basically you pay by reporting point the range is $0.05 - $0.13 per reporting point.
DeLorme inReach:

Spot Satellite Personal Tracker:

Spidertracks

Example of the web interface from Spidertracks for real-time tracking

I use my Android cell-phone freeware app called Oruxmaps. It records a very detailed and correct copy of your real-time track updated many times per second.
with only one drawback and that is altitude could be off by about a hundred feet.
it is also a surprisingly versatile navigation and moving-map app which allows you to use any set of charts or combination of them to fly. It gets your coordinates from your cellphone GPS, Or any tab with GPS like my Dell 8" tab.
You can set it to email your tracks to social network sites or anyone you want.
It records your tracks in small size files which you keep on a folder and can always superimpose them on Google Earth. I include some of my tracks photos I got using this app.

it doesn't look like this would be in real-time though, unless you linked it to Map My Tracks or some similar service.  Even then, it would require the use of cellular data which is still not allowed by the FCC, and even if it were, not a reliable solution. (see related: http://aviation.stackexchange.com/q/1481/132)

Looks like Catalina and Oxnard.

@PJNoes Yes it is Oxnard and Catalina. This freeware works with your phone GPS and is precise up to may be 10 feet. You can also set it up to automatically send out stress texts if you are not on time on you waypoint, or destination. I usually use it just for navigation and down load my tracks later.

You should consider aquiring an ADS-B transmitter. This is the new standard, growing rapidly, and it's what lets you be visible in sites like flightradar24 or others.
AFAIK, it uses your transponder in mode S to broadcast (to air AND ground) a bunch of information, like aircraft position, speed, altitude, heading, ...etc.
It is already used by most commercial airliners, small jets, and even piston driven aircrafts, and is considered the technology to be used in the near future, in respect of the FANS-1/A specification.

This would need to be fitted to the aircraft itself. The OP specifically asked for a solution that does not require modification of the aircraft, as he flies more than one aircraft.


text:
Does the "west evens / east odds" rule apply when flying without a specific destination (sightseeing, etc)?
I understand about the rule about odd / even (+500ft) separation at altitudes above 3,000ft AGL, but what about when you're flying without a definitive destination such as sightseeing where your track might change often? I realize that the solution isn't to continuously change altitudes, but what is the generally accepted rule here?
UPDATE: To be clear, I'm not suggesting sightseeing above 3,000ft or anything like that, but rather what is the rule (if any) to help with safety in regards to collision avoidance when flying with no definitive track. Is it normal / expected to be able to simply just fly-about at any altitude?

Why would you be sight-seeing at 3000'+ AGL?

@RonBeyer, I have updated my question to clarify this.

After seeing your update I'm not sure what sort of answer you expect here. The obvious thing to do for safety is to follow the regulations and fly at the appropriate altitude. If you don't do that, you're endangering people who do follow the rules and - of course - yourself too. If you have a specific scenario in mind - or you can invent a realistic one - it would be great to add it to the question.

@Pondlife, here is another example of what I'd be referring to: What about practicing maneuvers that involve altitude changes? You don't have a set heading, you aren't going from point A to point B. Furthermore, what if you wanted to practice those maneuvers within an altitude that would maybe put you in the WEEO rule? When with my flight instructor, we simply did the maneuvers and "watched for traffic". But is there a rule around this or can you simply fly at any altitude if you're not in level cruising (baring the rules about congested areas / none congested areas)?

Thanks for the example, but again I personally don't see an issue there. Apart from a few exceptions where altitude is needed for safety (e.g. spins), I've never done much training or practice above 3000 AGL and if I did, we were maneuvering a lot anyway and 91.159 wouldn't apply. In general, under VFR you can fly anywhere you like at any altitude provided you follow whatever rules apply to that airspace. I guess that one extra safety measure would be to ask for flight following (if it's available), you don't need to be following a specific route to get it.

I agree with @Rya

14 CFR 91.159 says:

Except while holding in a holding pattern of 2 minutes or less, or
  while turning, each person operating an aircraft under VFR in level
  cruising flight more than 3,000 feet above the surface shall maintain
  the appropriate altitude or flight level prescribed below, unless
  otherwise authorized by ATC: [etc.]

So if you're above 3000' AGL and not turning or in a hold, then you're required to follow the odd/even rule. Personally, I've never found it to be an issue because if I'm on a sightseeing flight or just following a river or whatever for fun then I'm usually below 3000' AGL anyway (and 91.159 is one of the reasons why).

If it's willy-nilly altitude and heading sightseeing flying, I would say it isn't "under VFR in level cruising flight."

@RyanMortensen If you're really climbing and turning all over the sky then I'd agree, it isn't level cruising flight. But turning is a specific exception in the regulation anyway.


text:
How do the European ATC strikes affect us as pilots?
So every once in awhile I see an article talking about the air traffic control strikes in Europe like this one:  European air traffic controllers to strike.
How does this affect me if I am flying to Europe?  Do they just close the doors and all airspace becomes uncontrolled airspace?  I'm guessing not, but that's what I envision when I hear that!  What happens if they go on strike while I'm over the ocean on my way there?

There are a couple of NOTAMs on page 2 & 3 here that might help someone formulate an answer: http://www.pprune.org/rumours-news/523784-europe-wide-atc-strike-10-october.html

Since these strikes are announced in advance, you will not be caught by surprise half way accross the ocean. If you try to file a flightplan through the soon to be closed airspace, the CFMU will not accept your plan. There will be no IFR traffic in the airspace before they close down the service.
I don't know about VFR.